Evolve or Perish is similar to Chutes and Ladders. It begins 635 million years ago, with the first multi-celled organisms. Each square on the board represents 10 million years. On the path to the present, numerous fates await you: slip on an early animal and go back one square; land on the Cambrian Explosion and jump ahead; land on the largest extinction event the world has ever known and go back nine spaces. The game is populated by cute animals (the first four-legged animal wears a party hat!) and strange-looking plants (like Lycopods from the coal swamps of the Carboniferous). All of the beautifully drawn creatures represent real plants and animals, known from the fossil record; a taxa list helps you learn your Oxynoticeras from your Omeisaurus. As you move your game piece from the past to the present, Earth's major milestones appear along the way – you'll pass meteors, millipedes, and the rise of giant mammals. The first player to make it to the present day wins the game – but experiences a gross revelation about how some of Earth's first inhabitants inhabit us humans, too.

Not to be rude, but what in the world is a rudist? Well, rudists are invertebrates, and they lived in the world’s oceans during the late Jurassic and the Cretaceous, about 150-65 million years ago; they are now extinct. They are bivalves  the name means “two shells.”Today’s familiar bivalves, clams and mussels, have two shells that are more or less symmetrical. But rudists were a bit unusual: their two shells were very different from each other. One shell was either conical or coiled, and it was attached to the ocean floor (or neighboring rudists). The other shell sat on top, like a little hat. The organism lived inside. They were probably filter feeders, feeding on plankton in the water, like many other bivalves today.

Rudists would grow on top of one another and form rudist reefs. They were the major reef-building organisms of their time  corals weren’t so abundant back then. Reefs are really important habitats for other marine organisms, like fish and crustaceans. So rudists played an important role in the ancient ocean.

So if rudists were so ecologically important, how did they get stuck with such an odd name?Lamarck dubbed them rudists in 1819, but it’s a little unclear what he meant. The Latin word rudis means rude, raw, or uncultivated. The Latin word rudus means rubble, or broken stone  specifically, the stones that made up Roman roads. Rudists do seem sort of coarse and unrefined, and they do look an awful lot like stones. But who knows what Lamarck was thinking.

This fossil rudist was found in Chiapas, Mexico. Learn more about rudists on the UCMP’s rudist page.